Portable hot line carrier current coupling device



Feb. 15, 1944. so 2,341,519

PORTABLE HOT LINE CARRIER CURRENT COUPLING DEVICE 1 Filed Oct. 51, 19412 Sheets-Sheet 1 Feb. 15, 1944. J. F 'ATK|NSQN 2,341,519

PORTABLE HOT LINE CARRIER CURRENT COUPLING DEVICE 1941 2 Sheets-Sheet 2Filed Oct. 31

w r m N5 K T mg a A K F El m n J Patented Feb. 15, 1944' UNITED STATESPATENT OFFICE PORTABLE HOT LINE CARRIER CURRENT COUPLING DEVICE (Grantedunder the act of March 3, 1883, as amended April 30, 1928; 370 O. G.757) Claims.

The invention described herein may be manufactured and used by or forthe Government of the United States for governmental purposes withoutthe payment to me of any royalty thereon in accordance with theprovisions of the act of April 30, 1928 (Ch. 460, 45 St. L. 467).

The invention pertains to a coupling device for carrier currentcommunication and more particularly to a portable coupling device whichmay be quickly and safely attached to a power line for the purpose oftransmitting or receiving messages without drainage of, interruption toor effect upon the voltage normally impressed upon or energy transmittedover the power line.

It is a known fact that electromagnetic and electrostatic fields are setup in the vicinity of a power line due to an impressed carrier currenton the line. It is further known that these electromagnetic andelectrostatic fields can be utilized to convey intelligence to nearbymoving and stationary vehicles that are equipped with suitable receiverstuned to the frequency of the carrier current. Communication by theseknown means and methods i but a one-way system.

Impressing a high frequency carrier current on a power line can beaccomplished by means of a suitable coupling capacitor or a suitableantenna erected near the power line.

It is the purpose of the present invention to provide a portablecoupling device that can be attached quickly and safely to a power linein order that two-way communication may be established between somefixed point and any other point on the power system. 4

Broadly, the present invention aims to accomplish a system of two-waycarrier current communication whereby a fixed or permanently locatedconventional carrier current station can communicate with suitablyequipped vehicles that are suiiiciently close to the power line to makeuse of the high frequency electromagnetic and electrostatic fields forsatisfactory receiver operation. In order for the suitably equippedvehicle to communicate with the permanently located conventional carriercurrent station it is necessary to make use of a portable couplingdevice in order to quickly and safely establish an electrical couplingto the power line for transmitting the high frequency carrier currentfrom the vehicle to the permanently located station. or vice versa.

The present invention also aims to facilitat twoway communicationbetween two or more suitably equipped vehicles or two or more portablecarrier current stations located at any desired points along the powerline by providing the aforesaid means as a portable, readily attachableand detachable coupling device.

The foregoing and other objects of the invention will become apparentfrom a reading of the following specification and appended claims. Anembodiment having the characteristic of my invention and by which thesame may be practiced is illustrated in the accompanying drawings, inwhich:

Figure 1 is an elevational view of the assembly illustrating anadaptation of the device;

Figure 2, an enlarged elevational view of the assembly;

Figure 3, a section in elevation of the upper portion of the deviceillustrating the interior assembly of elements of that portion;

Figure 4, a section in elevation of a portion of the device continuingfrom that of Figure 3 and illustrating the circuits and arrangement ofelements thereof Figures 5 and 6, cross sectional views taken alonglines 5-5 and 6-6 respectively of Figure 4; and

Figure 7, a wiring diagram illustrating the electrical circuits of thedevice.

It will become apparent to those versed in the art that the devicedescribed and claimed herein may be used, alternately, for transmittingand receiving intelligence by connecting the same to a transmitter orreceiving equipment. For a fuller understanding of the invention,however, the same will be described for use primarily in connection witha transmitter.

In the accompanying drawings the invention is illustrated asincorporated in a practical embodiment which includes a permeabilitytuned matching transformer Hi, the primary H of which is adapted to beconnected by leads l2 and [3 to a carrier current transmitter, notshown. and the secondary H of which is adapted to be connected betweenthe low side of a coupling capacitor or condenser I9 and the neutralwire I 6 of a power transmission line by leads l1 and I8, respectively.The condenser 19 is interposed in series between the secondary [4 of thetransformer I 0 and the point at which it is adapted to be connected toa phase conductor l5. For

safety purposes a liquid fuse 20 is placed in series between thecondenser 19 and the point at which the coupling device is adapted to behooked to the phase conductor 15. Further for safety purposes, leads I!and I8 are connected to a spark-gap 2! whereby excessive voltages, suchas surges due to lightning, switching. etc,

will by-pass the secondary l4 to the neutral wire l6 through conductorl8 and to ground by the customary ground lead 22. tionally contemplatesthe grounding of the chassis of the transmitter or receiver by theprovision of a lead 23 which is grounded directly to neutral wire I6 orcoupled to the ground lead 22 by means of a conductor l8.

In order that the foregoing system may be utilized as a portable unitand in order that the same may be readily and safelyconnected as well asdisconnected at and from desired points along a power line, I propose toutilize a portable carrier current transmitter, or receiver, such as maybe I installed in a truck or other vehicle or means of conveyance, andpropose installing the aforesaid system in a safe and easily handledhousing with appropriate connections for connecting the system todesired points in a power transmission line. With these aims in view Iprovide a housing of insulating material, which for assembly conveniencecomprises coupled tubular members 24, 25 and 26. By referenceparticularly to the detailed showings of Figure 3, it will be seen thatat the free end of housing member 24 is mounted a metal cap 21 fromwhich extends suitable means, such as a clip 28 into which a conductormay be removably wedged, for electrically engaging a power transmissionline. Any suitable liquid fuse 28, well understood in this art, isinserted within the housing member 24 and one end 29 thereof held ingood electrical contact with a metal plate 30, also mounted within thelatter housing member 24, by means of a spring 3| which serves as aconductor between the metal cap 21 and the other end 32 of the fuse. Themetal cap 21 may be provided with a safety plug 33 for the escape ofliquid and gases in the event of a breaking of the fuse seal. The safetyplug is of the character as will be removed by slight compressionalforce within the housing 24 to prevent a bursting thereof.

The condenser I9 is mounted within the housing 25 which is coupled tohousing 24 at its end opposite the metal cap 21 and the condenser is inturn connected to the fuse contact plate 30 such as by conductor 34.

For assemblying convenience the matching transformer may be mountedwithin a casing 35, see Figure 4, whereby it may be inserted, orremoved, as a unit into and from the housing member 25 beneath thecondenser and connected thereto by lead l'l. The matching transformer isadapted for permeability tuning by means of adjustment 36, Figure 4, orby any suitable means well understood in the art.

The carrier current leads l2 and I3 from the primary H of thetransformer, for connection to a transmitter, or receiver, as well asground leads I8 and 23 extend from the transformer casing 35 and housingmember 25 into housing member 26 and with the exception of lead l8 aresecured to terminals l2, l3 and 23', respectively, adjacent the free endof the housing member 26, Lead I8 for connecting the secondary l 4 andspark-gap 2| to the neutral wire l6 of a power transmission line passes,by connection 37, through the side wall of housing member 26 at a pointspaced from the clip 28 to a distance substantially that of the distancebetween the customary spacings between the phase and neutral wires of apower transmission line for reasons pointed out more specificallyhereinafter.

For connecting and disconnecting the transmitter or receiver to theassembly described, I

The system addiprovide a three-wire cable 38 having a plug 39 at the endthereof adapted to engage the terminals I2, I33 and 23'. For securingthe plug 39 to the base of the housing member 26 in contact with theterminals I provide a locking band 48 which may be rotated intooverlapping engagement between the end of member 39 of the housing andthe plug itself. Two of the wires of the cable 38 a are of course thelink wires for the transmission of the carrier current from atransmitter to the coupling device or from the coupling device to areceiver and the third wire of the cable may be connected directly tothe transmitter or receiver chassis which is mounted on and grounded tothe vehicle. The vehicle may be grounded by a separate lead 22' directlyto the ground or by a con nection, as shown in Figure l. to thecustomary ground lead 22.

The tubular housing member 26, of insulating material, is preferably ofsuch length as will serve as a handle or hot-stick for raising, loweringand, holding the device during application and removal to and from anenergized power transmission line.

In applying and operating the device I prefer for safety reasons tofirst ground the vehicle to which the transmitter or receiver chassis isgrounded, as indicated in Figure l, by lead 22'. Theportable couplingassembly may then be temporarily supported by clip 28 from the neutralwire N3 of the power transmission system during the time that lead I8 issecured to the power system neutral wire I6 by means of clamp 42. Clip28 may then be disengaged from the neutral wire l6 and the deviceelevated, by means of the insulating handle forming housing portion 26,into engagement with the power line phase conductor l5. Should suchsteps be followed it would be immaterial from a safety point as towhether the transmitter or receiver plug 39 were placed in engagementwith the coupling device terminals before or after the aforesaid stepsof installation.

For further reasons of safety I prefer that the length of so much of thelead l8 as extends from the housing be inadequate for connection to thepower line phase conductor l5 while the assembly is suspended by clip 28from the neutral wire I6 of the power system, thereby tending to limitthe connection of lead [8 to the neutral wire I6.

For still further reasons of safety a band 4| of metal or other materialmay be placed about the handle serving portion of the housing member 26above the normal grasping position of the handle as a marker or visiblewarning as well as a warning to the feeling senses of the operator as tothe danger zone of the device when in contact with the power lineconductors. The band 4|, if

' formed of metal, will also divert any charge,

which may be conducted by moisture along the surface of the housing, toground through lead 88 and prevent conduction to the handle portion ofthe device.

As a still further feature of safet I prefer to emplo some special formof clamping means for securing the lead l8 to the neutral conductor l6,special in the sense that it cannot be engaged by ordinary orconventional tools or hot-sticks but must be engaged with the hands as areminder that the connection is to be made to the neutral wire.

In case of coupling capacitor failures the safety spark-gap 2! willbreak down.

While the device described in connection with the specific embodimentillustrated is suitable as a coupling device for either a transmitter orreceiver, the primary and secondary windings may be exchanged in thehook-up without departing from the spirit or scope of the invention.Such an exchange may be preferred, though not necessary, in couplingdevices for connection to a re ceiver.

Having described my invention, what I claim is:

1. A portable device for coupling a carrier current transmitter orreceiver to a power line comprising: a rod-like member having a handlepor tion adjacent the lower end thereof, a conductive spring clamp atthe upper end of said member for engaging a live conductor of a powerline and suspending said member therefrom, a transformer, a fuse and acapacitor connected in series between one terminal of one winding ofsaid transformer and said spring clamp, means for grounding the otherterminal of said winding, leads from the other winding of saidtransformer for connection to a carrier current transmitter or receiver,said transformer, capacitor, and fuse being carried by and extendinglengthwise of said member with said fuse disposed adjacent said springclamp, with said transformer'in a position intermediate said fuse andthe lower end of said member, and with said capacitor in a positionintermediate said fuse and said transformer.

2. A portable device for coupling a carrier cur rent transmitter orreceiver to a power line comprising: a rod-like member having a handleportion adjacent the lower end thereof, a conductive spring clamp at theupper end of said member for engaging a live conductor of a power linand suspending said member thereform, a transfomer, leads from onewinding of said transformer adapted for connection to a carrier currenttransmitter or receiver, a capacitor having one terminal connected toone terminal of the other'winding of said transformer, mean forgrounding the other terminal of said other winding, a. fuse having oneterminal connected to the other terminal oflsaid capacitoigthe otherterminal of said fuse being connected to said spring clamp, andsafetygap means across said other winding, said transformer, capacitor,fuse and safety gap means being carried by and extending lengthwise ofsaid member with said fuse disposed adjacent said sprin clamp, with saidtransformer'in a position intermediate said fuse and the lower end ofsaid member, and with said capacitor in a position intermediate saidfuse and said transformer.

3, A portable device for coupling a carrier current transmitter orreceiver to a power Iine comprising: a hollow, sectional, rod-likemember having an insulator portion adjacent the lower end forming ahandle, a conductive spring clamp at the upper end of said member forengaging a live conductor of a power line and suspending said membertherefrom, a fuse within the hollow member end section adjacent saidspring clamp, a transformer and a capacitor within said hollow memberand below said end section, said fuse and said capacitor being connectedin series between one terminal 'of one winding of said transformer andsaid spring clamp, means for grounding the other terminal of saidwinding, and leads from the other winding of said transformer andextending axially from the lower end of said member for connection to a,carrier current transmitter or receiver.

4. A portable device for coupling a carrie current transmitter orreceiver to a power line comprising: a hollow, sectional, rod-likemember having an insulator portion adjacent the lower end forming ahandle, a conductive spring clamp at the upper end of said member forengaging a live conductor or a power line and suspending said membertherefrom, a fuse within the hollow member end section adjacent saidspring clamp, a transformer and a capacitor within said hollow memberand below said end section, said fuse and said capacitor bein connectedin series between one terminal of one winding of said transformer andsaid spring clamp, means for grounding the other terminal of saidwinding, leads from the other winding of said transformer and extendingaxially from the lower end of said member for connection to a carriercurrent transmitter or receiver, an exposed conductor ring incorporatedin said member above said handle portion and connected to said groundingmeans to conduct any leakage current to ground from the member portionabove said ring, and safety gap means across said one winding.

5. A portable device for coupling a carrier current transmitter orreceiver to a power line comprising: a tubular, sectional rod-likeinsulator member. a conductive spring clip carried at the tip of thetubular section at the upper end of said member for removably engaging alive conductor of a power line, a removable fuse within said end tubularsection and having one of its terminals connected with said spring clip,a removable coupling capacitor unit within a second tubular sectionadjacent said end section and having one of its terminals connected withthe other terminal of said fuse, a removable transformer unit includinga permeability tuned matching transformer and a casing therefor withinsaid second tubular section, a third tubular section forming the lowerend of said member and providing a handle, an exposed conductor ringencircling said member intermediate said handle and said second tubularsection to conduct any leakage current to ground from a point abovesaidring, a lead from said ring to a terminal of one winding of saidtransformer, said fuse and said capacitor being connected in series withsaid spring clip and the other terminal of said winding, and leads fromthe other winding of said transformer extending within said member andthrough said handle forming section for connection to a carrier currenttransmitter or receiver.

JOHN F. ATmNSON.

